JPS63151724A - Steel plate shell structure - Google Patents

Abstract

PURPOSE:To secure the stability of steel-plate shell as well as to raise the workability and economy of the shell without disturbing the surrounding ground by a method in which an air supply pipe serving in combination as an excavating compartment and a vertical rib is provided between the steel plate sheet body and the inner wall. CONSTITUTION:A vertical rib 2, a side rib 3, and a vertical rib 2' with an air supply pipe 6 are welded to the cylindrical steel plate of a steel plate shell 1. A cylindrical inner wall 4 lower than the shell 1 is provided in contact with the rib 2 inside the lower part to form compartments 5. A band steel plate 10 having a knife-shaped tip is welded to the lower end of the shell 1. Air is supplied through an air supply pipe 6 from an air compressor and jetted from the lower end to generate a gas-liquid mixed stream in the compartments 5 to disturb the soil particles of the bottom ground under water. The solid-gas- liquid mixed stream so formed is sent out and the penetrating resistance is removed to settle the shell 1 down.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to the structure of a steel plate cell used in port construction, river construction, etc., and is constructed using an air lift.

[Conventional technology]

Conventional methods for penetrating and sinking structures such as cell structures and caisson structures into the underwater ground include: - Installing a number of vibrohammers on the top of the structure and using their vibratory force to penetrate the ground; - Pre-excavation of the ground. However, there are two methods: one method is to backfill the structure after it has been installed, and the other method is to excavate the inside of the outer wall of the structure and sink it using the structure's own weight. However, in either case, large-scale and special equipment such as a large number of vibrohammers, ground excavation vessels, backfill equipment, and excavation equipment used inside the structure are required, and in some cases, divers are also required. Furthermore, for example, when using the vibrohammer 14 as shown in FIGS. 4(a) and 4(b), the weight and height of the vibrohammer 14 and the jig that supports it are large, so installation is difficult. A hoist with a lifting capacity that is at least commensurate with the weight and height of the structure to be lifted is required. In the figure, 1 is a steel plate cell, 7 is a hanging jig, 15 is a vibrohammer support jig, 16 is a chuck, and 17 is a damper.

Furthermore, in recent years, with the diversification of port and harbor construction, structures that previously protruded above the water surface are increasingly being constructed below the water surface. Alternatively, a long cell must be cut with an aerial vibrohammer and then cut at a predetermined height, which requires a large amount of cost.

In order to solve such problems, the applicant first applied the principle of an air lift pump and published Japanese Patent Application Laid-Open No. 176719/1986.
An application has been filed for a method and apparatus for penetrating a structure into underwater ground, which is disclosed in the above publication, and the gist thereof is as follows.

(1) Air is ejected downward from the lower end of the structure to be penetrated into the underwater ground, causing the particles that make up the ground below the structure to flow out, and the structure is inserted into the resulting cavity in the ground. to penetrate by its own weight.

(2) A rectifier plate arranged at a predetermined interval and facing the inner surface of the lower end of the outer wall plate of the structure to be penetrated into the underwater ground;
A pressurized air pipe for injecting air downward is provided near the lower end between the outer wall plate and the rectifying plate.

Figures 5 and 18), (b), and (C) are examples of the case where the penetration device of the above invention is applied to a steel plate cell, in which a cylindrical rectifying plate 18 with air supply pipes 19 attached at predetermined intervals on the outer periphery is shown. into the steel plate cell 1, and connect the air supply hose 9 to the air supply pipe 19.
Air is ejected downward between the steel plate cell 1 and the rectifying plate 18, disturbing the ground constituent particles, and penetrating the steel plate cell 1 into the underwater ground.

[Problem that the invention seeks to solve]

However, in the penetration device that applies the principle of the air lift pump described above, the air lift effect is applied to the slit between the steel plate cell and the rectifier plate installed inside it, so the generation of air flow due to air bubbles occurs in the circumferential direction. The excavation conditions of the ground are not uniform, and there are differences in the excavation conditions of the ground, resulting in poor efficiency. In addition, the amount of excavation outside the steel plate cells becomes large due to the flow that entrains the ground constituent particles, making backfilling necessary.

The purpose of this invention is to solve these problems, and to create a steel plate cell structure in which only the tips of the steel plate cells are excavated and the steel plate cells can be efficiently embedded in the construction method using an air lift pump. This is what we provide.

[Means for solving problems]

Hereinafter, an outline of the present invention will be explained using the numerals on page 1 corresponding to the embodiments.

In the steel plate cell structure of the present invention, while excavating the underwater ground below the steel plate cell l by the principle of air lift, a part of the vertical ribs constituting the frame of the steel plate cell l is used to embed the steel plate cell l into the ground. A pipe is used for this purpose, and this is used as an air supply vibro. Furthermore, a cylindrical inner wall 4 having a lower height than the steel plate cell 1 body is provided inside the cylindrical steel plate cell 1 body, and a plurality of compartments 5 are formed between the steel plate cell 1 body and the inner wall 4 by the vertical ribs 2 of the steel plate cell 1. Divided into. The above-mentioned air-feeding vibro and vertical ribs 2 as partitions are normally provided every other space, but it is also conceivable to arrange two or more air-feeding pipes 6 that also serve as vertical ribs in one compartment 5.

The construction involves installing the steel plate cell 1 at a predetermined position on the underwater ground using a hoist using a lifting jig 7, wire 8, etc., injecting air from an air supply vibro, and excavating the area directly below each compartment 5 using an air lift. Then, the steel plate cell 1 was sunk (.

The ground constituent particles lifted up by the air lift are mainly deposited inside the cylindrical inner wall 4.

[For production]

The basic principle of the method for submerging the steel plate cell 1 in this invention is as shown in FIGS. By creating a liquid multiphase flow, which disturbs the particles constituting the underwater ground, and transporting them as a solid, air, and liquid temperature phase flow, the penetration resistance at the tip of the structure is removed and the structure is submerged.

It is well known to transport underwater particles by pumping air, and is used, for example, in mining, dredging, etc., but in general, air lift pumps for mining, dredging, etc. The ratio H,/L of the height H3 to the water surface and the height L to the outlet of the solid/air/liquid temperature phase flow is Hs/
It is used where L<1, and its purpose is to remove particles constituting the ground. In the conventional example shown in Fig. 5 (a) to (C), as well as the present invention, from the beginning of the sedimentation process, Although Hs/L>1, there is no equivalent to compartment 5 in this invention, and the sinking efficiency is poor.

As for the amount of excavation by air pressure injection, when the same shape and the same number of air supply pipes are used under the air pressure, the amount of excavation of the underwater ground is the same regardless of the presence or absence of the compartment 5. However, by providing the compartment 5, it is possible to limit the excavation area directly below the compartment 5. This increases the amount of submergence per excavation amount (amount of steel plate cell subsidence) and enhances the effect of submergence. Furthermore, by carrying out the pneumatic feeding method according to the following steps, the sinking effect can be greatly increased.

B. At the initial stage of excavation, air is fed under pressure from all the air-feeding vibros, and the steel plate cell 1 is lowered by the required amount.

mouth, then increase the pneumatic delivery rate.

By the above-mentioned simple operation, the excavation location is reliably generated near the inner wall of the steel plate cell l and at the bottom of the compartment 5,
It can be submerged without disturbing the outside ground.

In other words, if there is no compartment 5, if a water supply route is established in the early stage of excavation, the excavation location will be limited, and even if the air supply to the relevant area is stopped, the flow pattern will not change, making it difficult to control the sinking. However, when the compartment 5 is provided, this point is greatly improved and the construction time is shortened.

〔Example〕

Next, the illustrated embodiment will be described.

FIGS. 2(a) and 2(b) show an embodiment of the present invention, in which the cylindrical steel plate of the main body of the steel plate cell 1 has a reinforcing vertical rib 2° and a horizontal rib 3, which are conventionally used for reinforcement. Welding the vertical rib 2' using the air supply pipe 6 according to the present invention,
A cylindrical inner wall 4 is provided in contact with the vertical rib 2 on the lower inner side thereof. A plurality of compartments 5 are formed by this inner wall 4, the cylindrical steel plate of the steel plate cell 1 body, and the vertical ribs 2. Further, a belt-shaped steel plate 10 whose tip is shaped into a knife shape is welded to the lower end of the cylindrical steel plate of the steel plate cell 1 body to reduce peripheral frictional resistance. The construction is as shown in Figure 1 above (
As shown in a) and (b), air from the near compressor is forced into the air supply vibro of the vertical rib 2 in each compartment 5 through the air supply hose 9, and the air is blown out from the lower end.

By using the air supply pipe 6 as a structural member of the steel plate cell 1 and reducing the height of the inner wall 4 to the effective minimum height, the weight is reduced, and accordingly, a hoist with a smaller lifting capacity than before can be used. .

FIGS. 3(a) and 3(b) show another example in which the upper end of the steel plate cell 1 is below the water surface by being submerged. In this case, a silt protector 1 made of a vinyl sheet or other flexible sheet is placed on the upper end of the steel plate cell 1.
2, and float 13 of silt protector 12.
Therefore, even if the rope cell 1 is submerged under the water surface, it is possible to prevent ground constituent particles such as earth and sand thrown up by the airlift from polluting the seawater.

〔Effect of the invention〕

According to the steel plate cell structure of the present invention, when the steel plate cell is submerged while excavating the underwater ground based on the principle of an air lift pump, an air supply pipe that serves as an excavation compartment and a vertical rib is provided in the frame of the steel plate cell itself. Therefore, the excavation area can be limited to just below the compartment of the steel plate cell. Therefore, according to this invention,
The speed of construction can be increased without disturbing the surrounding ground, and the particles constituting the ground are deposited inside the inner wall, ensuring the stability of the steel plate cell immediately after construction.

In addition, large-scale construction equipment such as a vibrohammer is not required, and a hoist suitable for the weight of the building frame can be used, improving construction efficiency and economic efficiency.

[Brief explanation of the drawing]

Figure 1 (al, (bl) are sectional views of the main parts at the initial stage of construction and at the completion of construction, respectively, showing the principle of the steel plate cell structure of the present invention,
Figures 2 (a) and (b) are respectively a front view and a plan view of one embodiment, and Figures 3 (a) and (b) are front views and a top view of another embodiment at the initial stage of construction and at the completion of submergence, respectively. Figure 4 (
al, (b) is a front view of the conventional example at the initial stage of construction and at the completion of submergence, respectively. figure(
C) is a horizontal sectional view thereof. 1.------・Steel plate cell, 2.------・Vertical rib, 3
・---1---Horizontal rib, 4...---1---Inner wall, 5-
・−・−・−・Compartment, 6・−・−・Air supply pipe, 7・・−・・−Hanging jig, 8−・−・−・−・Wire, 9−−−−−−1 Air supply pipe, 10--11--belt steel plate, 11-------accumulated earth and sand, 12
-------- Silt protector-113--111 --- Float. BS1 diagram (a) (b) Figure 2 (a) (a) (b>(b
)

Claims (1)

[Claims] (1) A cylindrical inner wall 4 having a lower height than the steel plate cell 1 body is provided inside the cylindrical steel plate cell 1 body, and the vertical ribs 2 of the steel plate cell 1 form a plurality of walls between the steel plate cell 1 body and the inner wall 4. A steel plate cell structure characterized in that it is partitioned into compartments 5 and each compartment 5 is provided with an air supply pipe 6 for air lift which also serves as a vertical rib of the steel plate cell 1.